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Lifetime Transmission Fluid

K

KIAman

Diamond Member
I hope TonyH chimes in. 😛

What are everyone's thoughts on lifetime transmission fluids? I want to get my ATF flushed but the dealer claims one should never touch it and it will last forever. They are "sealed" and should never be opened. That just sounds ridiculous to me. Do they not have a filter inside and the oil never gets dirty?

Maybe lifetime means 100k miles. To me that's a short lifespan with how much driving I do.
 
Complete crap. Sure it will last a lifetime, until the transmission blows itself to bits. Trans on our ES300 blew itself apart while we were driving it. It had lifetime fluid.

There is still a bit of debate in the BMW community about it. Some say change at 60k, some 100k. Others say, Ze Germans know everything, do not challenge them! IIRC ZF and BMW now recommend 100k changes.

Just talking with a Mercedes/BMW shop owner last week. He now does 60k changes with synthetic, 30k with regular fluid. He's had BMWs come in with poor shifting. Did a fluid and filter change and everything was fine. People come back a week later with the same problem. He couldn't figure out what it was until he cut the trans filter open. The brand new filter was already clogged. Had to do another fluid/filter change.
 
Synthetic ATF doesn't break down like it used to, but I would still recommend changing it to get metal particles and pieces of friction material out of the oil.
 
one thing to keep in mind is a lot of trannies with 'lifetime' fluid lack traditional filters, having nothing more than a mesh screen. it's assumed that friction material will accumulate in the fluid over time, and the TCM is supposed to compensate for it. in some cases, the adaptive values need to be reset when the fluid is changed.
 
It is ridiculous. The tranny still wears, and the fluid still gets dirty.

I remember Ford made a couple of models that didn't even have a dipstick to check the fluid level. They were no more reliable than the previous models.
 
The fluid in my 645 is supposed to be lifetime but I don't believe it. I'm just under 50k and, from an inexact pov, I'm starting to feel like it needs to be flushed. Don't ask what the dealership wants to flush it, I would do it but no dipstick.
 
So... I'm about to get an independent shop do a complete tranny flush, filter and fluid replacement. Thoughts?
 
2006 BMW 330i Sedan. I found parts for the filter, seals, bottom pan (I don't know if I need this), and fluids.
 
Have you talked to independent mechanics? There's lots of theories on flushing/not flushing and the benefits and drawbacks of each. Typically, if the filter isn't user replaceable, your best bet is to do a simple drain and fill.
 
Their definition of "Lifetime" is in reference to the lifetime of the transmission. Better quality (Synthetic and synthetic blends) will help by decreasing normal wear through improve lubrication properties but they won't stop the wear completely. Once that transmission dies that's the end of teh "Lifetime".

So called "sealed units" can be serviced with the proper tools and techniques. If the filter is easily accessible it should be changed.

Transmission with filters that can't be accessed with dismantling the transmission should never be flushed. I've seen more than my fair share of Hondas that were towed right from the flusher at the lube shop to my place. Customer's famous last words were "they said the flush would help".

 
The only consistent information I get is that the original fluid contains broken down friction materials from the internal transmission components and actually contribute to the function of the clutches. My follow up question is that does the friction material benefits outweigh other contaminants circulating through the transmission. Their consensus is, they don't know. Thus why I posted the OP.

I've also read that as soon as BMW started implementing free-maintenance, the transmission fluid recommendation went from 80k to suddenly lifetime... with no design or fluid changes. That concerns me.
 
It's a lifetime fluid, just need to replace the trans every 60K

My car (2000 A6 2.7t) has lifetime fluid according to the dealer. Well according to ZF, the manufacturer of the trans, the schedule is every 80K.

For audis the rule of thumb is to change the fluid and filer, but don't flush (agitates the settled material, which could lead to troubles).
 
Originally posted by: KIAman
2006 BMW 330i Sedan. I found parts for the filter, seals, bottom pan (I don't know if I need this), and fluids.
Click to expand...

It has a 5L40E which is the same transmission that they use in the Cadillac CTS. I wouldn't recommend flushing but a drain and fill with filter change should be done. Be careful with the pan gasket though. It should a metal gasket with bonded rubber for best results. Avoid cork or all rubber gaskets.
 
I replaced mine at 80k on my MPV and it was filthy in color, truly awful. I did not flush it. Many people don't like flushing older systems. I simply drained it out, ran the tranny a bit until it was totally empty, refilled it, then ran it through a few times until I had basically replaced all of it. I didn't bother doing the filter because I, well, I didn't bother.
 
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